2012 Volume 9 Issue 22 Pages 1742-1747
This paper presents the design of a lowpass filter (LPF) with high and ultra wide rejection in the stopband using stepped-impedance compact microstrip resonator cell (SICMRC). The proposed filter consists of a prototype stepped-impedance LPF, which is modified to form a double arrow shaped microstrip cell (DASMC) with a wide stopband. Then, SICMRC is embedded in the structure of the DASMC to obtain a sharp response. The attenuation level in the stopband is better than -20dB that is achieved from 6.6 to 41.7GHz. The proposed filter has low insertion loss less than 0.1dB and high return loss more than 26dB in the passband. The transition band is approximately 0.74GHZ from 5.86 to 6.6GHz with corresponding attenuation levels of -3 and -20dB. The cut-off frequency of the prototype filter is 5.8GHz. It has a simple shape and a compact size of 14.2mm × 8.2mm. The proposed filter has been designed, fabricated and measured. The Comparison between the simulation and experimental results shows that they are in good agreement.